Search Results for author: Alexandre Vignaud

Found 3 papers, 2 papers with code

SNAKE-fMRI: A modular fMRI data simulator from the space-time domain to k-space and back

1 code implementation12 Apr 2024 Pierre-Antoine Comby, Alexandre Vignaud, Philippe Ciuciu

We propose a new, modular, open-source, Python-based 3D+time fMRI data simulation software, \emph{SNAKE-fMRI}, which stands for \emph{S}imulator from \emph{N}eurovascular coupling to \emph{A}cquisition of \emph{K}-space data for \emph{E}xploration of fMRI acquisition techniques. Unlike existing tools, the goal here is to simulate the complete chain of fMRI data acquisition, from the spatio-temporal design of evoked brain responses to various multi-coil k-space data 3D sampling strategies, with the possibility of extending the forward acquisition model to various noise and artifact sources while remaining memory-efficient. By using this \emph{in silico} setup, we are thus able to provide realistic and reproducible ground truth for fMRI reconstruction methods in 3D accelerated acquisition settings and explore the influence of critical parameters, such as the acceleration factor and signal-to-noise ratio~(SNR), on downstream tasks of image reconstruction and statistical analysis of evoked brain activity. We present three scenarios of increasing complexity to showcase the flexibility, versatility, and fidelity of \emph{SNAKE-fMRI}: From a temporally-fixed full 3D Cartesian to various 3D non-Cartesian sampling patterns, we can compare -- with reproducibility guarantees -- how experimental paradigms, acquisition strategies and reconstruction methods contribute and interact together, affecting the downstream statistical analysis.

Image Reconstruction

Is good old GRAPPA dead?

2 code implementations1 Jun 2021 Zaccharie Ramzi, Alexandre Vignaud, Jean-Luc Starck, Philippe Ciuciu

We perform a qualitative analysis of performance of XPDNet, a state-of-the-art deep learning approach for MRI reconstruction, compared to GRAPPA, a classical approach.

MRI Reconstruction

Robust imaging of hippocampal inner structure at 7T: in vivo acquisition protocol and methodological choices

no code implementations9 May 2016 Linda Marrakchi-Kacem, Alexandre Vignaud, Julien Sein, Johanne Germain, Thomas R Henry, Cyril Poupon, Lucie Hertz-Pannier, Stéphane Lehéricy, Olivier Colliot, Pierre-François Van de Moortele, Marie Chupin

Multi-slab registration yielded high quality datasets in 96 % of the subjects, thus compatible with further analyses of hippocampal inner structure. CONCLUSION:Multi-slab acquisition and registration setting is efficient for reducing acquisition time and consequently motion artifacts for ultra-high resolution imaging of the inner structure of the hippocampus.

Hippocampus

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